Orthodontic brackets which are attached to the teeth of a patient, are designed to engage an archwire that exerts force upon the teeth to move the teeth into various clinically appropriate orientations. Such brackets typically include an archwire slot for reception of the archwire. Those skilled in the art will recognize that an archwire slot can have any desired cross-sectional configuration, or size, to match the size and shape requirements of the archwire or wires that are being received within the same slot.
Heretofore, many orthodontic brackets have been adhesively bonded to a tooth with the archwire slot being oriented in a substantially parallel orientation relative to the occlusal plane. However, those skilled in the art have long recognized that the archwire slot can also be angularly oriented across the bracket for certain clinical applications. Previously, orthodontic brackets have included various cleat-like extensions which have been referred to in the art as tie-wings or lugs. These structures project upwardly and downwardly, typically in pairs, at the top and bottom of the installed orthodontic bracket. In this regard, these extensions permit an archwire to be held within the archwire slot of the bracket by means of a twisted wire (a ligature) or an elastomeric o-ring which is releasably affixed by the respective lugs or tie-wings.
In U.S. Pat. No. 4,248,588 to Hanson, and which issued on Feb. 3, 1981, an orthodontic bracket, and archwire were disclosed and which included a moveable retainer member which, in one position, could be located in a position which facilitated access to the archwire slot, and in a second position, was useful for retaining the archwire within the archwire slot. Still further, this same reference disclosed a passageway 74 which is defined, at least in part, by the body of the bracket, and which is useful, in one embodiment, to pass a thin tie wire through, but which also was found advantageous, when fabricated in a rectangular cross-section, to receive a secondary archwire which could be employed to provide additional corrective forces to the tooth upon which the orthodontic bracket was attached.
In my U.S. Pat. No. 5,466,151, I disclosed a spring-locked orthodontic bracket having a ligating slide and which was acted upon by a biasing spring of various configurations which exerted an anteriorly outwardly biasing force thereagainst the moveable ligating gate in order to position or secure it in an appropriate orientation relative to the archwire slot.
In my U.S. Pat. No. 6,071,118, I disclosed a self-ligating orthodontic bracket having a transverse archwire slot and which further included a moveable, ligating slide which cooperated with the orthodontic bracket in order to achieve various benefits not possible, heretofore, in orthodontic brackets having a similar design.
In addition to the foregoing, the Carriere SLB orthodontic bracket which has recently been introduced by Class One Orthodontics includes a bracket body with a moveable cantilevered ligating slide. This orthodontic bracket further includes resilient members which form an integral portion of the ligating slide and which cooperate with the superior portion of the bracket body to releasably secure the ligating slide in a closed position. In this arrangement, the members forming an integral portion of the ligating slide exert a force on the ligating slide which is substantially coaxially aligned relative to the path of travel of the ligating slide. The resilient members otherwise do not support the distal end of the ligating slide when it is located in closed position over the archwire slot. Thus, the ligating slide remains cantilevered relative to the archwire slot.
While the brackets of the prior art have worked with varying degrees of success, assorted shortcomings have detracted from their usefulness. In particular, one of the chief difficulties with brackets having the designs as discussed, above, relates to the accurate manufacturing of same. Still further, another shortcoming attendant with such prior art devices relates to the dimensional size of such brackets. As should be understood, practitioners, as well as patients, have continually sought after smaller, and more inconspicuous brackets in order to acquire or achieve a more aesthetically acceptable appearance when the bracket has been installed in the mouth of a patient. As will be clear from reviewing the several earlier mentioned prior art references, the positioning of a biasing member within the bracket body in order to biasingly cooperate with the ligating gate has typically increased the dimensional size of the resulting bracket, and further increased the difficulty associated with fabricating and assembling orthodontic brackets of this type. Additionally, orthodontic bracket designs such as the Carriere SLB have additional shortcomings. For example, in brackets of this prior art design, if an archwire is not fully seated in the archwire slot, it becomes difficult if not impossible to fully engage the ligating slide with the bracket body thereby securing the ligating slide in the closed position over the archwire. More specifically, in a design such as seen in the Carriere SLB, and wherein the cantilevered ligating slide must releasably engage the base member in order to remain closed over the archwire slot, it will be readily apparent that an unseated archwire may deflect or deform the ligating slide sufficiently so that it may not effectively engage the base member, and therefore remain closed over the archwire. In this specific design, if the ligating slide does not effectively engage the base member, a clinician may cause the ligating slide to complete disengage from the base member with the result that the base member must now be removed from the patients tooth, and a new orthodontic bracket attached to the tooth to continue treatment. This is obviously a time consuming process for both the clinician as well as the patient.
An orthodontic bracket which avoids many of the shortcomings attendant with the prior art practices and orthodontic bracket designs utilized heretofore, is the subject matter of the present application.